I think it would be easiest to explain this bug with an example.
Suppose you have job A configured to poll SVN for changes (ie: using the default SVN plugin for Jenkins), so after a change is detected a build is triggered. Further suppose that this job has a post-build Action configured to trigger another job, job B. After job B finished, you can view the summary information about the build. Part of that summary displays the upstream jobs that were triggered previously - with links to the specific build numbers of each. Also there is a link entitled "Started by an SCM change".
Now, if you click this link on the downstream job (job B in this case) you get nothing. This is because the link refers to the SVN polling log for job B instead of the polling log for the originating job that actually had a modification in the repository, job A in this case.
Now I'm not sure if this is a bug with a core system in Jenkins, the SVN plugin or maybe some other plugin I have installed. I have a relatively small set of plugins installed and none of them seem to require interaction with SVN or the build summary pages so I doubt those are at fault.
Either way this is an annoying bug because it forces developers to click through several links to get to the details of the origin of the failure. It would be nice to see this fixed.
I am using the latest version of the SVN plugin (1.48) and the LTS version of Jenkins (v1.509.1)